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as the horizontalmember over a building voidsupported at its ends by twovertical

columns,

pillars, or

posts.This architectural system andbuilding method has beencommonly used for centuries tosupport the weight of thestructure located above theopenings created by windowsand doors in a

bearing wall.

From prehistoric times to the Roman Empire, the post–

and–

lintel system

was the root of architectural design. The interiors ofEgyptian temples and the

exteriors of Greek temples are delineated by columnscovered by stone lintels. The

Greeks opened their interior spaces by substitutingwooden beams for stone, since the

wood required fewer supports. The development ofthe arch and vault challenged the

system but could not diminish its importance either inmasonry construction or in

wood framing, by its nature dependent on posts andbeams

The job of the post is to support the lintel and its loads withoutcrushing or buckling. Failure occurs, as in lintels, from excessiveweakness or length, but the difference is that the material must beespecially strong in compression. Stone, which has this property,is more versatile as a post than as a lintel; under heavy loads it issuperior to wood but not to iron, steel, or reinforced concrete.Masonry post, including those of brick, may be highly efficient,since the loads compress the joints and add to theircohesiveness. Although monolithic stone columns are used, theyare extravagant to produce for large structures, and columns areusually built up of a series of cylindrical blocks called drums.